When articles are conveyed, it is generally practiced that each article is provided with an information medium, to which identification information is given, so as to identify and manage the each article. Bar code labels, hole IDs each identified by a position of a hole, wireless tags (also called IC tag, RFID or the like) and the like are used as the information media. When bar code labels or hole IDs are used, IDs of articles are fixed and thereby the IDs cannot be reused. Since bar code labels are usually made of paper, they are discarded after each use. In many cases, therefore, bar code labels are directly affixed to articles to be conveyed.
Meanwhile, the information storage capacity of bar code labels is small. When bar code labels need to store a large amount of information, therefore, they are not suitable. In contrast with this, RFIDs have the advantage that the storage capacity thereof is large. However, RFIDs are expensive in comparison with bar code labels, and thus it is not desirable to discard the RFIDs after each use. For this reason, erasing information written to an information recording medium and rewriting information thereto makes it possible to reuse the information recording medium or a conveying table provided with the information recording medium. Patent Documents 1 to 5 disclose examples in which RFIDs are used.